Thank you for posting.
"Err 30" indicates that malfunctions related to the power source have been detected.
1. Turn off the camera.
2. Remove the battery from the camera.
3. Using a microfiber cloth, thoroughly clean the contacts on the battery. Do this even if the contacts already look clean.
4. Retry the battery in the camera.
If the error still occurs, please try an alternate battery. If the alternate battery produces the same results, your camera will require service to correct the issue.
To start the repair process, you'll need to complete a Repair Request on our website.
I have started my err 30 investigation using this forum and want to share my experience. I have solved the problem.
Camera: Rebel T3i, 3 years old 12, 050 clicks
Got camera wet ( salt water ) but never submerged. Sure enough - err 30...
Tried everything - nothing worked. Call Cannon, $190 + shipping. If they can fix it, of course.
Worst case scenario - wasted money on shipping, 3 weeks later I am in square one.
Timing was not in my favor so I went to a couple local shops. First shop told me camera is beyond repair, rusty and economically unfeasible to fix. The second shop when heard about water damage flatly refused even to look
They also told me canon people will not touch it as well if water is involved.
OK, new camera body or new camera then
I was repairing TV, VCR etc when I was a kid. Not like I can fix the camera with all these micros and potentially damaged shutter box. But it was worth to try. Less then hour later I got camera working again. Not sure how long it will last, nevertheless:
1. remove the cover, it is easy, you can follow this:
2. use magnifying glass and inspect the whole board, especially connectors. I noticed traces of salt and corrosion
3. I have used alcohol, piece of cloth, sharp metal object ( needle would do it ) and cleaned up the surface
4. Inserted battery and voila, camera works again
5. Final inspection, dried the board and put camera together
24 hours later camera work OK, no err 30 whatsoever. No grantee it will not appear again ( salted water is nasty )
I'll make an update if I see err 30 again
I hope this comment can help somebody
Issue started when I was photographing the Christmas parade in cold weather, and it was also damp out. Changed batteries with one I took out of my other camera, same issue. Wasn't till I returned home and put another battery in it that cleared up the issue.